Generally, in a mobile communication network, such as the Long Term Evolution (LTE) or the LTE-Advanced (LTE-A) of the 3rd Generation Partnership Project (3GPP), two user terminals communicate with each other via a base station (evolved Node B (eNB) in the LTE). However, the requirements for efficient use of network resources and the needs for new services or service models may lead to applying direct device-to-device (D2D) communication. The D2D communication, or mobile-to-mobile, terminal-to-terminal, or peer-to-peer communication may be employed within the mobile communication network.
The direct D2D communication comprises at least two relatively closely located devices communicating with each other directly instead of a conventional communication link for end-to-end (E2E) communication, in which the source device transmits data to the destination device via the eNB. The two devices in the D2D communication may apply radio resources of the mobile communication network, thus sharing the resources with devices that are communicating with the eNB in the conventional link. This may lead to challenges in the radio resource allocation performed by the eNB. Further, the quality of service (QoS) of the E2E communication may suffer from the decisions related the radio resource allocation, a data transport method (the D2D communication link versus the conventional link), and the like, governed by the eNB.
Consequently, for the sake of performing reliable D2D communication, reducing transmitter power, increasing the capacity and coverage of the network, and creating and supporting services for the users, it is important to provide a solution for more efficient use of the D2D communication in a mobile communication network.